Overlapping peptides of melanocyte differentiation antigen Melan-A/MART-1 recognized by autologous cytolytic T lymphocytes in association with HLA-B45.1 and HLA-A2.1.
From the peripheral blood lymphocytes (PBLs) of melanoma patient SK29(AV) we have previously isolated 2 independent cytolytic T lymphocyte (CTL) clones (CTL7/147 and CTL13/211), which lysed autologous tumor cells in association with HLA-B45.1. As demonstrated here, both CTL clones were directed against melanocyte differentiation antigen Melan-A/MART-1, which also was recognized by HLA-A2.1-restricted CTLs from the same patient. By generating and transfecting 3'-deletion mutants of Melan-A/MART-1 cDNA, we localized its peptide-coding regions. The HLA-B45.1-presented peptides were derived from a hydrophobic region of the protein and largely overlapped the peptides recognized by CTLs from the same patient in association with HLA-A2.1. We determined the fine specificity of these CTL clones with synthetic peptides. CTL clone CTL7/147 recognized the 11-mer peptide AEEAAGIGILT (residues 24-34) at the lowest concentrations. The absence of threonine-34 abrogated the recognition by CTL7/147. The truncated peptide AEEAAGIGIL (residues 24-33) proved to be the optimal synthetic peptide for sensitization against lysis by CTL13/211. This indicated that C-terminal threonine-34 was not involved in binding to HLA-B45.1 but, rather, was part of the epitope for CTL7/147. HLA-B45.1-associated peptides of Melan-A/MART-1 were regularly processed and presented by other melanomas and other cell types. Three of 4 independent HLA-A2.1-restricted SK29-CTL clones recognized the 10-mer peptide EAAGIGILTV (residues 26-35) at 10- to 100-fold lower concentrations than the nonamer AAGIGILTV (residues 27-35), previously described as the common immunodominant peptide antigen for all known anti-Melan-A/MART-1 CTLs restricted by HLA-A2.1. Different melanoma peptide antigens currently are applied in therapeutic vaccination studies. Our findings emphasize that restricting to peptides of minimal length might exclude relevant T-cell epitopes.
Schneider
J
J
I Medizinische Klinik und Poliklinik, Johannes Gutenberg-Universität, Mainz, Germany.
Brichard
V
V
Boon
T
T
Meyer zum Büschenfelde
K H
KH
Wölfel
T
T
D000595:Amino Acid Sequence; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D019556:COS Cells; D004273:DNA, Neoplasm / Q000235:genetics; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D015789:HLA-A2 Antigen / Q000276:immunology*; D015235:HLA-B Antigens / Q000276:immunology*; D006801:Humans; D058965:MART-1 Antigen; D008545:Melanoma / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology*; D017386:Sequence Homology, Amino Acid; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D004273:DNA, Neoplasm; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D015235:HLA-B Antigens; C077377:HLA-B45 antigen; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins